The formation of ammonia from litter in broiler houses depends on various factors such as climate (both inside and outside the house), dry matter content of the droppings, and dry matter content, pH, ammonium content and temperature of the litter. However, it is not known how these processes interact with and / or influence each other. For this reason, Wageningen UR Livestock Research performed a study in which the effect of environmental conditions and dry matter content of the droppings on litter characteristics (pH, temperature, dry matter, nitrogen and ammonium content) and ammonia emission was investigated. The objective of this study was to gain knowledge in the relationships between environmental climate conditions, litter characteristics and ammonia emission from broiler houses. This study shows that it is possible to reduce ammonia emissions from broiler houses through management measures. Especially measures that increase the dry matter content of the litter and / or decrease the ammonium content of the litter and / or decrease the pH of the litter will reduce the ammonia emission.